There is a gear pump used as an oil-pressure source for movable bodies such as construction machines, robots, and automobiles (see JP 10-252589 A (PTL 1)).
In a gear pump disclosed in PTL 1, a pump assembly includes: a pair of gears that have rotary shafts pivotally supported by a gear case and circumscribed and engaged with each other; a pair of side plates that seal side surfaces of the gears; and the pump assembly configured with a seal block that seals tooth tips of the gears in the vicinity of an intake port are housed in the gear cases, and a pressure division seal (seals for dividing pressure into intake pressure on the inside and discharge pressure on the outside) is installed in a groove on end surface of the side plate or the seal block on the gear case side. The pressure division seal is formed from an elastic body such as rubber such that the side plates and the gear side surfaces are brought into light touch with each other by an initial load of the elastic body. The cross section of the pressure division seal is stepped to produce space into which the pressure division seal (rubber) can escape even though the pressure division seal is bulged in the groove.